Brushless DC Motor Control System Research Based On FPGA

Recently, Brushless DC Motors have developed rapidly. They are widely applied to industrial field for the reason that they have the advantage of both DC Motors and AC motors: huge torque, high efficiency, excellent dynamic performance, simple structure and stable operation. However, with the development of Aerospace industry, people are going to make demands on Brushless DC Motors from the aspect of controlling precision and stability. Traditional simulation control circuits are huge in size, low in integration and easier to be interfered by environment factors. Regular PID’s control has low precision and inflexible. Therefore, a Brushless DC Motor controlling system should be designed to meet the needs of the growing industry.This thesis designs a Brushless DC Motor digital controlling system which controlling chip wears FPGA (Field Programmable Gate Array). Using FPGA’s logical calculating capability, high integration and small size, we could achieve the goal of having a more complicated and intelligent controlling system, enhancing motors’precision and stability. Control algorithm is parameter self-tuning PID which combines intelligent control algorithm and regular PID. The controlling parameter changes with the condition of system automatically that enhances Brushless DC Motors’ real-time controlling ability and its dynamic performance. In addition, this thesis adapts PWM_ON_PWM, which means every working switch uses30°forwards and30°backwards PMW,60°in-between adjusting mode that decreases diode freewheeling of the inactive phase. To some degree, this adjusting mode restrains the motor’s torque ripple and enhances the stability of motor’s rotate speed.In the beginning, this thesis has introduced the structure and theories of Brushless DC Motors, including the model of Brushless DC Motors, analyzing the theory of fuzzy self-tuning PID control algorithm and finding out the implement method. Afterwards, this thesis explains the torque ripple of Brushless DC Motors, putting forwards PWM_ON_PWM and using Matlab/Simulink to test the fuzzy self-tuning PID and PWM_ON_PWM. Then, basing on the explanation of the controlling system of FPGA Brushless DC Motors’s software and hardware, this thesis adapts Altium Designer to design the hardware circuit of peripheral system. The author compiles the inner functional module of FPGA by using Quartus Ⅱ. In the last, the thesis tests the controlling system of Brushless DC Motors based on FPGA and results in a fine working motor, which means a proper system design and goal achievement.